Future Human Studies

In future human studies, there are two critical goals. First, studies should be conducted to establish the accuracy and reproducibility of TSI and ARFI imaging in a representative population of human subjects. These factors are of critical importance and will strongly influence the potential clinical impact of TSI and ARFI imaging. Aside from the technical issues with the imaging modalities that have already been discussed, one important choice that must be determined for such a study is the gold standard against which TSI and ARFI imaging will be compared. Histology has long been the benchmark against which non-invasive imaging modalities were graded. However, comparisons between histology and imaging data are rife with complicating factors including, but not limited to, different slice thicknesses, deformation of tissue during the embedding and cutting process, and challenging image co-registration. For these reasons, multi-contrast MRI might be a suitable alternative to histology. In MRI, there is

Additionally, MRI is able to obtain isotropic 3-D volumes, which might more accurate and easy co-registration of images.

Depending on the results of this first study, subsequent studies should be directed towards identifying the clinical utility of combined TSI and ARFI imaging. As was previously mentioned, the concept of the vulnerable plaque is well-established, but there is little high quality evidence to support clinical intervention based off of this concept. A randomized, double-blind study is the gold standard for clinical evidence and could be used to establish protocols for the manner in which TSI and ARFI imaging findings would influence CEA intervention. Specifically, this study would be structured to randomize asymptomatic patients with high-grade stenosis and clinically worrisome findings on TSI and ARFI imaging into either a surgical or medical arm. Such a study would help to definitively establish whether a soft, lipid rich necrotic core or a thin fibrous cap were predictors of future, adverse cerebrovascular outcomes. Additional studies to establish the efficacy of longitudinal monitoring and the effects of medical therapies on plaque stabilization could also be pursued. Overall, if the remaining technical challenges facing TSI and ARFI imaging are addressed, there are a number of clinically significant studies that could be pursued that could have an important impact on clinical practice.

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